Technical Field
The present disclosure relates to a vehicle seat that is provided with a side airbag device.
Related Art
In a side airbag device for a vehicle seat that is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2003-341461, a burst line portion which is a seam line (i.e., a seam portion) in the seat back upholstery receives inflation pressure from the side airbag, and ruptures. Reinforcement fabric that is used to concentrate the inflation pressure from the side airbag in the burst line portion is suspended between the burst line portion and the seat back frame. In this reinforcement fabric, a seam edge that is sewn in the seat back upholstery so as to follow the burst line portion is formed longer than a join edge where the reinforcement fabric is joined to the seat back frame.
In this vehicle seat, in some cases, in order to improve the aesthetic appearance, the seam portions in the seat back upholstery are set in a complex configuration. For example, in some cases, a three-way junction of seam portions is formed by providing a seam portion that branches off from the seam portion that forms the burst line portion.
In the case of this type of structure, in the aforementioned three-way junction, a loss occurs during the transmission of the load needed to rupture the burst line portion. If, as a result of this, a delay occurs in the rupturing of the burst line portion, there is a possibility that the side airbag will not inflate and deploy in the desired position.